This is all nonsense. Tablet’s Yair Rosenberg challenged progressive followers to recommend right-wing writers “about whom you would not be offended if they were hired by the NY Times/Atlantic/Washington Post/etc?” You would not know reading this question or the griping from Carney, McLaughlin, and all the others that before Williamson, those three publications already employed, by my cursory and possibly incomplete count, 18 conservatives and libertarians writing regularly for them: David Brooks, Bret Stephens, Bari Weiss, Ross Douthat, David Frum, Conor Friedersdorf, Reihan Salam, George Will, Charles Krauthammer, Megan McArdle, Marc Thiessen, Max Boot, Michael Gerson, Jennifer Rubin, Kathleen Parker, Radley Balko, Ed Rogers, and Anne Applebaum. The majority offer their takes frequently and freely without liberals on Twitter or anywhere else jeering in mass protest. None would raise more than a few grumbles if lateral moves were made between those publications—if the Atlantic hired Max Boot, say, or if Kathleen Parker went to the Times.
Individual liberals and leftists will differ on which voices in conservative media they think should be added to that roster, but generally speaking, the majority of that list suggests the left is almost entirely indifferent to establishment conservatives and libertarians writing for centrist and center-left publications, so long as those conservatives aren’t overly caustic or trollish. As much as some junior staffer at the Washington Free Beacon might want to believe he’d be martyred by a social media mob if he were picked up by the Washington Post, no one, in all likelihood, would bat an eye.